Apparatus for removal of liquid from moving filamentary yarns



APPARATUS FOR REMOVAL OF LIQUID FROM MOVING FILAMENTARY YARNS Filed Sept. 7, 1966 K. H. CRAM July 9, 1968 2 Sheets-Sheet l July 9, 1968 K. H. CRAM 3,391,672

APPARATUS FOR REMOVAL OF LIQUID FROM MOVING FILAMENTARY YARNS Filed Sept. 7, 1966 2 Sheets-Sheet Q United States Patent 3,391,672 APPARATUS FOR REMOVAL OF LIQUID FROM MOVING FELAMENTARY YARNS Kenneth H. Cram, Waynesboro, Va., assignor to E. I. du

Pont de Nemours and Company, Wilmington, Del., a

corporation of Delaware Filed Sept. 7, 1966, Ser. No. 577,727 3 Claims. (Cl. 118-126) ABSTRACT OF THE DISCLOSURE An apparatus for removing liquid from filamentary yarns moving in substantially vertical paths through at least one liquid bath. The apparatus includes a deflector bar and a guide position positioned above the bath on opposite sides of one path of upward travel. The structural shape of the bar and guide along with their positional relationship with respect to each other and to the upwardly traveling yarn functions to effectively remove entrained liquid from the yarn.

This invention rel-ates to liquid treatment of continuously moving shaped structures and more particularly to the liquid treatment of continuous filaments, yarns, tows and the like, singly or in combination.

In the continuous production of shaped structures such as filaments, yarns and tows, it frequently is necessary to bring such structures into intimate contact with a treating liquid for a variety of reasons. One case in point may have the objective to saturate a water-wet tow comprising continuous filaments with a topical finish or lubricant; thorough coating of all filaments requires displacement of the water by the finish solution. Extraction of a solvent from a filamentary tow is more complex since multiple complete displacements of the adherent film of extraction liquor are required for eflicient, continuous processing. Even the simple process of stretch-orientation of a filamentary structure in a hot liquid bath will operate more efliciently if the shaped structure is frequently stripped of the adherent layer of liquid to permit an approach toward equalization with the baths temperature.

Efforts toward the objective of improved contact efficiency with a treatment bath have taken a number of forms. It is common practice to employ multiple baths of treating liquids, in which liquid flows countercurrent to the direction of the shaped structure when extraction of, for example, a residual solvent is an objective. To

minimize carryover of solvent-rich extraction liquor to subsequent baths, quetsch rolls are frequently employed on the rolls which guide the shaped structure between baths. Such a roll-wringer effect is not completely satisfactory. Liquor is pumped through the nip between yarn objection to the fluid jets is found in their high cost of operation.

This invention provides means for eflicient removal of liquid from continuous, moving shaped structures. It fur ther provides means for removal of liquids from continuous, moving shaped structures without damaging mechanical contact therewith.

These and other advantages are provided in this invention by an improvement in apparatus for and process of contacting with a liquid treating agent shaped structures of the class consisting of filaments and aggregations thereof such as yarns and tows, said improvement comprising the use of at least one substantially horizontally mounted liquid-deflector bar in conjunction with at least one guide surface oriented adjacent to the opposite sides, respectively, of at least one path of upward travel of said shaped structure after the immersion thereof in said treating agent, said deflector bar having an under-surface with a radius of curvature of at least 2 inches (5 cm.) said surface being inclined upwardly toward the yarn path, its terminal angle of approach to the yarnbeing at most about an upper surface merging with the yarn-approaching edge of said under-surface at a relatively sharp angle, the resulting sharp edge being: positioned adjacent to said yarn path immediately above said guide surface, said guide surface having a radius of curvature in close proximity to said deflector bar of at least about 0.25 inch (0.6 cm.) on the upper surface thereof, said combination of deflector bar and guide surfaces serving to deflect and draw, respectively, the entrained liquid treating agent across and through the moving aggregation of shaped structures.

While operable dimensions will obviously vary depending on the material treated, speed of operation, viscosity of the liquid treating agent and so forth, it is found that for most uses it is preferable that the terminal angle of approach to the yarn for the under-surface of the deflector bar be in the range of 45 to 90, that the sharp edge formed by the underand upper-surfaces be from 10 to 90, and that the radius. of curvature of the guide surface in close proximity to the deflector bar be about 0.25 to about 4.0 inches (0.6 to 10 cm.).

The unique combination of a curved guide surface and a closely associated, upward angled, somewhat curved or flat plate terminating in a sharp edge is of particular value in more rapidly eliminating liquid from filaments and ag gregations thereof when said filaments carry a relatively thick film of liquid. Although it is not intended to limit this invention by a mechanistic concept, it is probable that its elfectiveness lies in'the high momentum of the deflected film of liquid which imparts lateral motion to the remaining adherent liquid. The curved upper edge of the guide surface serves to draw the removed water away from the filament path. A circular-cross-section rod having a radius of from about 0.25 to about 4.0 inches (0.6 to 10 cm.) will channel some of the liquid back to the yarn path for restripping as it strikes the deflector bar. This type finds utility in those cases where the film of liquid is of borderline thickness for best operability of the deflector bar. Where an amply thick film of liquid is present, it is more efiicient to employ a guide in which the curved, upper surface merges with a downwardly in clined surface so as to deflect all stripped liquid away from the yarn path.

This invention will be more readily understood by reference to the following discussion taken with the figures in which:

FIGURE 1 is an overall schematic view of a multiple- =bath extraction-drawing apparatus representing one embodiment of this invention;

FIGURE 2 is a cross sectional view taken along line 22 of FIGURE 1;

FIGURE 3 is an enlarged detail of the deflector barguide assembly employed in the process of this embodiment;

FIGURES 4 and 5 are schematic representations of apparatus employed in conjunction with the apparatus of FIGURE 1 to determine the degree of liquid carryover with and without the deflector bar-guide assembly of this invention; and

FIGURES 6, 7, 8 and 9 illustrate some alternate shapes which may be employed with the deflector barguide assembly.

With reference to FIGURE 1, continuous filamentary tow 1 (from source not shown) passes over idler rolls 2 and into baths 3 in which are located driven rolls 4. The tow passes over rolls 4 and upwardly to subsequent idler rolls 2 successively in each of the several extraction-draw tanks. Fresh extraction liquid is supplied at 5 (from source not shown) and flows counter-currently, relative to the direction of tow travel to the first tank 3 from which it is pumped (by means not shown) for recovery of the solvent it contains. Rolls 4 are profiled in speed to provide the desired amount of orienting stretch. Tow emerging at 6 from the final extraction draw bath is forwarded (by means not shown) to subsequent stages of processing involving drying, optionally cutting to staple, and packaging. As tow 1 rises from the baths, it contacts grooved guides 7 which serve to maintain proper distribution of the filaments across the length of rolls 2 and 4. Deflector bars 8 are oriented adjacent to the path of the filament just above grooved guide 7 as is illustrated in greater detail in FIGURE 3. As can be seen in FIGURE 2, both the aggregation of grooved guides 7 and the deflector bars 8 in this embodiment extend over the full width of the sheet of yarns comprising the tow. With reference to FIGURES '6, 7, 8 and 9, it is seen that a variety of cross-sectional shapes are satisfactory for the guides, the only requirement being that from the point of contact with the upwardly inclined path of the filaments aggregation the guide be contoured such that its upper surface proceeds in an upwardly and outwardly direction in a radius of curvature of at least about 0.25 inch (0.6 cm.), and preferably from about 0.25 to about 4 inches (0.6 to 10 cm.).

The amount of liquor entrained by a warp of individual yarn ends rising out of a bath is strongly dependent on yarn speed and spacing. Differences in entrainment rate are apparent in a change in the elevation of the liquid ridge oriented along the line of emergence of the yarn ends from the liquid and in a change in the amount of spray projected from idler rolls 2. A further effect of a speed increase is the entrainment of a film of liquid between running ends which results in merging individual ends of yarn. Guiding means such as represented by grooved guides 7 prevent further loss of liquid-contact efliciency and straying of individual filaments which would otherwise result.

FIGURES 4 and 5 schematically represent liquid collection devices employed to measure the amount of easily separable, entrained liquid under various process conditions. Yarn ends 1 are diverted from their normal downward paths 12 to wrap around rolls 9 and 10. Spray collectors L L and L, are installed in such a way as to collect the liquid thrown from the yarn ends as they break over rolls 2, 9 and 10, respectively. The following example illustrates this invention in comparison with prior art. Liquid collected at L is separately tabulated, but it will be recognized that differences between the totals of all three collections of liquid are representative of the improvements aiforded by this invention.

Example A warp sheet comprising 4 ends of 100 filament, 8.8

denier per filament yarns is produced by dry-spinning a 4 sheet is threaded through an extraction-draw machine such as schematically depicted in FIGURE 1 and introduced continuously at 90 or 100 y.p.m. (82 or 91 meters/ min.). During the passage through the first seven tanks, the sheet is drawn to 415% of its original length. Thus as it merges from the seventh bath it is traveling at 373 or 415 yards (340 to 379 meters) per minute. A grooved guide having an outside diameter of about 1.5 inches (3.8 cm.) and a groove-seat diameter of approximately 1 inch (2.5 cm.) in diameter is provided in each tank for each end of yarn. The centerline of the guides is positioned 8 inches (20 cm.) above the static level of liquid in the tank and one-half inch outside the normal path of the emerging yarn so that each end of yarn makes brushing contact with the smaller external diameter of one guide. A deflector bar having a long dimension somewhat longer than the warp sheet, cross-sectional dimensions of 0.5 x 2.5 inches (1.27 x 6.35 cm.) and shaped to provide a sharp-edged 30 approach to the yarn path is positioned so that its undersurface is at a angle to the yarn path and the sharp edge approaches, but does not touch, the yarn at a point immediately above the grooved guide.

The table summarizes the results of the tests conducted with and without the deflector bar. The grooved guides were used in all tests. L L and L represent the weight of liquid removed per unit weight of yarn under each set of conditions.

TABLE Filament Emergence Speed Pounds of liquid collected Deflector per pound of yarn Bar? m./min. L1 L2+L Total It is thus apparent that the addition of the deflector bar provides means to greatly enhance the eflicient removal of liquids from continuous, shaped structures.

One skilled in the art of treating shaped structures with liquids will recognize numerous possibilities for operative embodiments other than those described but which lie within the spirit and scope of this invention. It is intended, therefore, that this invention be limited only as detailed in the attached claims.

What is claimed is:

1. In apparatus for contacting filamentary yarns with a liquid treating agent, wherein the filamentary yarns are moved alternatively upwardly and downwardly in substantially vertical paths through liquid bath, the improvement comprising at least one substantially horizontally mounted liquid-deflector bar and at least one guide, said bar and said guide being disposed on opposite side of at least one path of upward travel of said yarns subsequent to the treatment thereof with said liquid, said deflector bar having an undersurface with a radius of curvature of at least two inches which undersurface is inclined upwardly toward the yarn path at a terminal angle of approach to said yarn path of at most about degrees and said deflector bar having an upper surface merging with the yarn-approaching edge of said undersurface at a relatively sharp angle, the resulting sharp edge formed thereby being positioned substantially adjacent to said yarn path immediately above said guide, the upper surface of said guide having a radius of curvature in close proximity to said deflector bar of at least about 0.25 inch.

2. Claim 1 wherein said terminal angle of approach of the undersurface of said deflector bar to said yarn path is in the range of from about 45 degrees to about 90 degrees and wherein said sharp angle is in the range of from about 10 degrees to about 90 degrees.

3. Claim 2 wherein the radius of curvature of the up- 5 per surface of said guide in close proximity to said defiector bar is from about 0.25 inch to about 4.0 inches.

References Cited UNITED STATES PATENTS 2,051,403 8/1936 Boyer et 211. 2,711,156 6/1955 Bawling 118126 XR 2,739,338 3/1956 Weeks 15-100 2,787,242 4/1957 Williamson et a1. 118-126 2,894,559 7/1959 Eccher 118126 XR 2,936,468 5/1960 Iverson 15-100 XR.

FOREIGN PATENTS 470,144 12/1950 Canada.

CHARLES A. WILLMUTH, Primary Examiner. R. I. SMETH, Assistant Examiner. 

